Communication system, mobile station, base station, response decision method, resource configuration decision method, and program

ABSTRACT

It is possible to solve the problem that a downstream control information amount is significantly increased if allocation information is periodically reported because no allocation method of a default E-DCH resource configuration is defined for a preamble signature. A base station and a mobile station decide a default resource configuration by using a total number of resource configurations or a value obtained from the total number.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/617,120, filed Jun. 8, 2017, which is a continuation of U.S.application Ser. No. 15/188,451, filed Jun. 21, 2016, which is acontinuation of U.S. application Ser. No. 14/567,466, filed Dec. 11,2014, which is a continuation of U.S. application Ser. No. 14/037,007,filed Sep. 25, 2013, which is a continuation of U.S. application Ser.No. 12/920,419, filed Aug. 31, 2010, which is a national stage ofPCT/JP2008/072122 filed Dec. 5, 2008, claiming priority from JapaneseApplication No. 2008-072580, filed Mar. 19, 2008, the disclosures ofwhich are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to an uplink data channel resourceallocation method and related techniques.

BACKGROUND ART

In W-CDMA (Wideband Code Division Multiple Access), which is athird-generation mobile communications system, a mobile station (UE:user equipment) in a CELL_FACH (Forward Access Channel) state has nospecific base station to which it is subordinate, and selects a basestation each time the mobile station transmits control information orthe like. The operation of RACH (Random Access Channel), which is anuplink data channel, is stipulated in a specification of thestandardization project, 3GPP (3^(rd) Generation Partnership Project),for third-generation mobile communications systems (see Non-patentDocuments 1 through 4, for example). Moreover, in 3GPP Release 8, atechnique for enhancing RACH, E-RACH (Enhanced RACH), is being studied(see Non-patent Document 5, for example). An operation of E-RACH will bebriefly described with reference to FIGS. 1 through 3 hereinbelow.

FIG. 1 is a block diagram showing a configuration of a mobilecommunications system. For preventing complexity of explanation here, itis assumed that a plurality of mobile stations 20-1, 20-2, 20-3, . . . ,20-N are located in a cell 40 of a base station 10, and the mobilestations are in a CELL_FACH state. The base station 10 is assumed to beconnected to an upper network apparatus 30. It should be noted that fordesignating an arbitrary mobile station, it will be designated as“mobile station 20” hereinbelow.

FIG. 2 is a channel schematic diagram showing a relationship in E-RACHbetween a preamble, AICH or AICH and E-AICH (which will be designated asAICH/E-AICH hereinbelow), and E-DCH; and FIG. 3 is a sequence chart ofchannel settings for E-RACH and others. As shown in FIG. 2, in an uplinkcommunication, there are an uplink data channel E-DCH (EnhancedDedicated Channel), and a preamble for coordinating timing oftransmission before transmitting E-DCH. In a downlink communication,there are a downlink channel AICH (Acquisition Indicator Channel) forresponding to the preamble received from the mobile station, and E-AICH(Extended AICH) for allocating an E-DCH resource configuration, whereAICH and E-AICH are transmitted with the same channelization code foreach cell. It should be noted that some base stations do not supportE-AICH. In a case that a base station does not support E-AICH andtransmission with a default E-DCH resource configuration cannot beachieved, a mobile station performs transmission of the preamble againafter a predetermined period of time. As used herein, the term ‘default’refers to an E-DCH resource configuration index corresponding to apreamble signature.

The preamble employs a preamble signature Csig,s, and a spread codereferred to as preamble scrambling code Sr-pre,n, which will bedescribed below. The preamble signature Csig,s is composed of 4096 chipsin which an Hadamard code having a code length of sixteen is repeated256 times, and the preamble scrambling code Sr-pre,n is a cellidentification code emitted by a base station. A preamble signatureCsig,s is randomly selected by each mobile station from predeterminedpreamble signatures (Csig,1, Csig,2, . . . , Csig,$), where n designatesthe index of a scrambling code.

A k-th value of preamble code data Cpre,n,s is constructed from acorresponding k-th preamble signature Csig,s from among 4096 chips and acorresponding preamble scrambling code Sr-pre,n, and is given by EQ. (1)as follows:

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack & \; \\{{C_{{pre},n,s}(k)} = {{S_{{r - {pre}},n}(k)} \times {C_{{sig},s}(k)} \times e^{f{({\frac{\pi}{4} + {\frac{\pi}{2}k}})}}}} & (1)\end{matrix}$

where

k=0, 1, 2, 3, . . . , 4095,

Cpre,n,s: preamble code data,

Sr-pre,n: a preamble scrambling code, and

Csig,s: a preamble signature.

An uplink data channel E-DCH is composed based on a specificationstipulated in 3GPP Release 6 (see Non-patent Document 6, for example).

An overview of the operation of E-RACH is shown in FIGS. 2 and 3. Thebase station 10 periodically broadcasts an E-DCH resource configurationlist including an E-DCH resource configuration for use in E-RACH and acorresponding E-DCH resource configuration index, a preamble signaturelist including preamble signature numbers available in E-RACH, and theaforementioned preamble scrambling code, to mobile stations within thecell using BCH (Broadcast Channel).

The E-DCH resource configuration is comprised of E-RNTI (Enhanced RadioNetwork Temporary Identity), E-AICH Configuration Flag, Uplink DPCH(Dedicated Physical Channel) Info, E-DCH Info, E-AGCH (E-DCH AbsoluteGrant Channel) Info, E-RGCH (E-DCH Relative Grant Channel) Info, E-HICH(E-DCH Hybrid ARQ indicator Channel) Info, Downlink F-DPCH Info, TTI,E-DCH Start Time, and the like.

The mobile station 20 transmits preamble code data to the base stationwith an initial transmit power value calculated from the amount ofreceive power in a pilot channel of the base station 10. The preamblecode data is generated using the preamble scrambling code emitted by thebase station 10 and a preamble signature randomly selected by the mobilestation. The base station 10 transmits a responsive notification(ACK/NACK) for the received preamble using the AICH signature state tothe mobile station 20. In a case that the mobile station cannot use thedefault E-DCH resource configuration because, for example, anothermobile station uses it, the base station 10 that supports E-AICH sends aresponsive notification using AICH, and information representing theE-DCH resource configuration to the mobile station using E-AICH.

For example, in a case that the base station 10 has successfullyreceived the preamble transmitted by the mobile station, and allowsuplink data to be transmitted using a default E-DCH resourceconfiguration allocated for each preamble signature contained in thepreamble, the base station 10 sends a responsive notification ACK usingAICH.

On the other hand, in a case that the base station 10 does not allowuplink data to be transmitted using the default E-DCH resourceconfiguration, it sends a responsive notification NACK using AICH.Moreover, for a base station that supports E-AICH, in a case that thebase station does not allow uplink data to be transmitted using thedefault E-DCH resource configuration but allows the uplink data to betransmitted using a non-default E-DCH resource configuration, it sendsan offset value indicating an E-DCH resource configuration index allowedto be used to the mobile station using E-AICH according to a methodwhich will be described later.

In a case that uplink data is not allowed to be transmitted even using anon-default E-DCH resource configuration, the base station sends aresponsive notification NACK using AICH to the mobile station.Information indicating whether or not the base station supports E-AICHis broadcast to mobile stations within the cell using E-AICHConfiguration Flag included in BCH.

In a case that the mobile station 20 has received a responsivenotification using AICH, and the response for the preamble signatureused in transmission of the preamble is ACK, the mobile station 20determines an E-DCH transmission profile from a default E-DCH resourceconfiguration allocated to the transmitted preamble signature and theinitial transmit power value for the E-DCH calculated from the transmitpower value for the transmitted preamble, and transmits the data to thebase station 10.

The mobile station can know whether the base station supports E-AICHfrom E-AICH Configuration Flag mentioned above. In a case that the basestation supports E-AICH, and a response to the preamble signature usedin transmission of the preamble is NACK, the mobile station receivesE-AICH. On the other hand, in a case that the base station does notsupport E-AICH, and a response to the preamble signature used intransmission of the preamble is NACK, the mobile station transmits thepreamble again after a predetermined period of time. In a case that noresponse to the preamble signature used in transmission of the preambleis received, the mobile station 20 decides that the preamble transmittedbefore is not received by the base station 10, and unless the upperlimit of the number of retransmissions is reached, it retransmits thepreamble with a transmit power increased by a predetermined amount. In acase that E-AICH is received and the responsive notification for E-AICHis not NACK, an E-DCH transmission profile is determined from an E-DCHresource configuration corresponding to an offset value obtained fromthe E-AICH signature number and the E-AICH signature state included inE-AICH, and the data is transmitted to the base station 10. In a casethat the responsive notification is NACK, transmission of the preambleis performed again after a predetermined period of time.

It should be noted that, as shown in FIG. 2, a minimum preambleretransmission interval tip-p,min, and an interval τp-a from a preambleto transmission of a responsive notification in AICH are predetermined.For a preamble signature corresponding to a preamble that cannot berecognized by the base station because, for example, the preamble cannotbe received at the base station although it was transmitted by themobile station, no response is made from the base station to the mobilestation. In a case that no response is made until τp-a, the mobilestation retransmits the preamble.

AICH transmits a responsive notification (ACK/NACK) using the AICHsignature state corresponding to the preamble signature Csig,s of thepreamble. AICH is composed by combining 32 codes ‘aj’ derived from EQ.(2) below, and the signature pattern bs,j for AICH is defined in Table 1(see Non-patent Document 4, for example), where s designates an AICHsignature number, and bs,j may take sixteen patterns. Moreover, AIsindicates the AICH signature state, which takes AIs=+1 when theresponsive notification for AICH is ACK, or AIs=−1 when it is NACK.

$\begin{matrix}\left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack & \; \\{a_{j} = {\sum\limits_{s = 0}^{15}{{AI}_{s}b_{s,j}}}} & (2)\end{matrix}$

TABLE 1 s b_(s, 0), b_(s, 1) . . . , b_(s, 31) 0 1 1 1 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 2 1 1 1 1 −1 −1 −1−1 1 1 1 1 −1 −1 −1 −1 1 3 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 1 4 11 1 1 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 1 5 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1−1 −1 1 1 1 6 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 1 7 1 1 −1 −1 −1−1 1 1 −1 −1 1 1 1 1 −1 −1 1 8 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 −1 9 1 1−1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 −1 10 1 1 1 1 −1 −1 −1 −1 1 1 1 1 −1−1 −1 −1 −1 11 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 −1 12 1 1 1 1 1 11 1 −1 −1 −1 −1 −1 −1 −1 −1 −1 13 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1 −1 −1 11 −1 14 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 −1 15 1 1 −1 −1 −1 −1 11 −1 −1 1 1 1 1 −1 −1 −1 s b_(s, 0), b_(s, 1) . . . , b_(s, 31) 0 1 1 11 1 1 1 1 1 1 1 1 1 1 1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 2 1 1 1−1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 3 1 −1 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 14 1 1 1 1 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 5 1 −1 −1 1 1 −1 −1 −1 −1 1 1 −1−1 1 1 6 1 1 1 −1 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 7 1 −1 −1 −1 −1 1 1 −1 −11 1 1 1 −1 −1 8 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 9 −1 1 1 −1−1 1 1 −1 −1 1 1 −1 −1 1 1 10 −1 −1 −1 1 1 1 1 −1 −1 −1 −1 1 1 1 1 11 −11 1 1 1 −1 −1 −1 −1 1 1 1 1 −1 −1 12 −1 −1 −1 −1 −1 −1 −1 1 1 1 1 1 1 11 13 −1 1 1 −1 −1 1 1 1 1 −1 −1 1 1 −1 −1 14 −1 −1 −1 1 1 1 1 1 1 1 1 −1−1 −1 −1 15 −1 1 1 1 1 −1 −1 1 1 −1 −1 −1 −1 1 1

E-AICH is composed by combining 32 codes ‘aj’ derived from EQ. (3) belowusing the same channelization code as that for AICH. The E-AICHsignature pattern cs,j is defined in Table 2 (see Non-patent Document 7,for example), where s′ designates an E-AICH signature number, and cs,jmay take sixteen patterns at maximum. Moreover, EAIs' designates theE-AICH signature state, and the state of only one E-AICH signature isused per access slot among one or more E-AICH signature numbers to sendthe offset value to the mobile station.

Table 3 is a table representing an example of correspondence between anE-AICH signature state, an E-AICH signature number, and an offset valueindicating an E-DCH resource configuration index. X designates a defaultE-DCH resource configuration index corresponding to a preamblesignature, Y designates the total number of E-DCH resourceconfigurations. The offset value in Table 3 indicates an offset from theE-DCH resource configuration index allocated by default in the E-DCHresource configuration list. For example, when the E-AICH signaturestate is +1 and the E-AICH signature number is zero, the offset from theE-DCH resource configuration index allocated by default is one. WhenE-AICH is decoded to obtain an offset of one, the mobile stationperforms data transmission using an E-DCH resource configurationcorresponding to the E-DCH resource configuration index obtained byadding one to the E-DCH resource configuration index allocated bydefault.

On receipt of E-AICH, the mobile station decodes E-AICH using the E-AICHsignature pattern. Decoding of E-AICH may be achieved in a manner inwhich the E-AICH signature is arranged in order, such as in the order ofthe E-AICH signature starting from #0, for example, and the E-AICHsignature is determined in partial decoding, or in a manner in whichafter all E-AICH signatures are decoded, an E-AICH signature estimatedto have the highest probability is determined. An offset value isdetermined from the E-AICH signature number obtained by decoding E-AICH,and the E-AICH signature state. An E-DCH resource configurationcorresponding to an E-DCH resource configuration index designated by thedefault E-DCH resource configuration index and obtained offset is usedto determine an E-DCH transmission profile.

[Equation 3]

a _(j) =EAI _(s′) c _(s′,j)  (3)

TABLE 2 signature Resource EAI_(s′) s′ configuration index +1 0 NACK −1(X + 1) mod Y +1 1 (X + 2) mod Y −1 (X + 3) mod Y +1 2 (X + 4) mod Y −1(X + 5) mod Y +1 3 (X + 6) mod Y −1 (X + 7) mod Y +1 4 (X + 8) mod Y −1(X + 9) mod Y +1 5 (X + 10) mod Y −1 (X + 11) mod Y +1 6 (X + 12) mod Y−1 (X + 13) mod Y +1 7 (X + 14) mod Y −1 (X + 15) mod Y +1 8 (X + 16)mod Y −1 (X + 17) mod Y +1 9 (X + 18) mod Y −1 (X + 19) mod Y +1 10 (X +20) mod Y −1 (X + 21) mod Y +1 11 (X + 22) mod Y −1 (X + 23) mod Y +1 12(X + 24) mod Y −1 (X + 25) mod Y +1 13 (X + 26) mod Y −1 (X + 27) mod Y+1 14 (X + 28) mod Y −1 (X + 29) mod Y +1 15 (X + 30) mod Y −1 (X + 31)mod Y

TABLE 3 s c_(s, 0), c_(s, 1) . . . , c_(s, 31) 0 1 −1 1 −1 1 −1 1 −1 1−1 1 −1 1 −1 1 −1 1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 2 1 −1 1−1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 3 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 11 −1 1 4 1 −1 1 −1 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 1 5 1 −1 −1 1 1 −1 −1 1−1 1 1 −1 −1 1 1 −1 1 6 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 1 −1 1 −1 1 7 1 −1−1 1 −1 1 1 −1 −1 1 1 −1 1 −1 −1 1 1 8 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1−1 1 −1 −1 9 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 −1 10 1 −1 1 −1 −11 −1 1 1 −1 1 −1 −1 1 −1 1 −1 11 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 1 −1−1 12 1 −1 1 −1 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 −1 13 1 −1 −1 1 1 −1 −1 1−1 1 1 −1 −1 1 1 −1 −1 14 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 1 −1 1 −1 −1 151 −1 −1 1 −1 1 1 −1 −1 1 1 −1 1 −1 −1 1 −1 s c_(s, 0), c_(s, 1) . . . ,c_(s, 31) 0 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 1 −1 −1 1 1 −1 −1 1 1−1 −1 1 1 −1 −1 1 2 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 −1 1 3 −1 −1 1 −1 11 −1 1 −1 −1 1 −1 1 1 −1 4 −1 1 −1 1 −1 1 −1 −1 1 −1 1 −1 1 −1 1 5 −1 −11 1 −1 −1 1 −1 1 1 −1 −1 1 1 −1 6 −1 1 −1 −1 1 −1 1 −1 1 −1 1 1 −1 1 −17 −1 −1 1 −1 1 1 −1 −1 1 1 −1 1 −1 −1 1 8 1 −1 1 −1 1 −1 1 −1 1 −1 1 −11 −1 1 9 1 1 −1 −1 1 1 −1 −1 1 1 −1 −1 1 1 −1 10 1 −1 1 1 −1 1 −1 −1 1−1 1 1 −1 1 −1 11 1 1 −1 1 −1 −1 1 −1 1 1 −1 1 −1 −1 1 12 1 −1 1 −1 1 −11 1 −1 1 −1 1 −1 1 −1 13 1 1 −1 −1 1 1 −1 1 −1 −1 1 1 −1 −1 1 14 1 −1 11 −1 1 −1 1 −1 1 −1 −1 1 −1 1 15 1 1 −1 1 −1 −1 1 1 −1 −1 1 −1 1 1 −1

-   Non-patent Document 1: 3GPP TS25.214 v7.5.0, May 2007-   Non-patent Document 2: 3GPP TS25.321 v7.2.0, September 2006-   Non-patent Document 3: 3GPP TS25.331 v7.3.0, December 2006-   Non-patent Document 4: 3GPP TS25.211 v7.2.0, May 2007-   Non-patent Document 5: 3GPP RP-070677, Nokia Siemens Networks,    Nokia, Ericsson, Qualcomm, T-Mobile, Telecom Italia, “Enhanced    Uplink for CELL_FACH State in FDD,” September 2007-   Non-patent Document 6: 3GPP TS25.319 v7.3.0-   Non-patent Document 7: 3GPP R1-080835, Qualcomm Europe, Ericsson,    Nokia, Nokia Siemens Networks, Motorola, “25214CRdraft (Rel-8, B),    RACH procedure relation to Enhanced Uplink for CELL_FACH state,”    January 2008

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The E-RACH system proposed by Non-patent Document 7 may be incorrectlyoperated because a method of allocation of a default E-DCH resourceconfiguration for a preamble signature in the E-DCH resourceconfiguration list is not defined. Common methods for solving theproblem that may be contemplated include a method of broadcasting from abase station a default E-DCH resource configuration index to beallocated for each preamble signature using BCH; however, the methoduses four bits to specify sixteen preamble signature numbers at maximum,and five bits to specify thirty-one E-DCH resource configuration indicesat maximum, which requires 144 bits at maximum to allocate default E-DCHresource configurations to all preamble signatures, resulting in aproblem that the amount of downlink control information is significantlyincreased by periodically broadcasting the allocation information usingBCH.

It is therefore an object of the present invention to provide a defaultresource configuration allocation method and apparatus that can preventan increase of the amount of broadcast information.

Means for Solving the Problems

The present invention for solving the aforementioned problems is acommunications system comprised of a base station and mobile stations,characterized in that the base station receives a preamble transmittedby the mobile station, and transmits a response to the received preambleto the mobile station, and in a case that the response is a firstresponse, the mobile station transmits data using information about atleast a part of a default resource configuration of the own mobilestation that is determined using the total number of resourceconfigurations or a value obtained from the total number.

The present invention for solving the aforementioned problems is a basestation, characterized in that the base station determines a responsivenotification in response to a preamble transmitted by a mobile stationbased on a default resource configuration determined using the totalnumber of resource configurations or a value obtained from the totalnumber.

The present invention for solving the aforementioned problems is amobile station for transmitting a preamble to a base station,characterized in that the mobile station receives a response to thepreamble from the base station, and in a case that the response is afirst response, the mobile station transmits data using informationabout at least a part of a resource configuration that is determined asa default resource configuration of the own mobile station using thetotal number of resource configurations or a value obtained from thetotal number.

The present invention for solving the aforementioned problems is aresponse determination method for a base station, characterized incomprising determining a responsive notification in response to apreamble transmitted by a mobile station based on a default resourceconfiguration determined using the total number of resourceconfigurations or a value obtained from the total number.

The present invention for solving the aforementioned problems is aresource configuration determination method for a mobile station,characterized in comprising determining a default resource configurationusing the total number of resource configurations or a value obtainedfrom the total number.

The present invention for solving the aforementioned problems is aprogram for causing an information processing apparatus to executeprocessing, the program being characterized in causing the informationprocessing apparatus to execute processing of determining a responsivenotification to be transmitted by a base station in response to apreamble transmitted by a mobile station based on a default resourceconfiguration determined using the total number of resourceconfigurations or a value obtained from the total number.

The present invention for solving the aforementioned problems is aprogram for causing an information processing apparatus to executeprocessing, the program being characterized in causing the informationprocessing apparatus to execute processing of determining a defaultresource configuration in a mobile station using the total number ofresource configurations or a value obtained from the total number.

Effects of the Invention

According to the present invention, a default resource configuration canbe allocated while preventing an increase of the amount of broadcastinformation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A block diagram showing a configuration of a mobilecommunications system.

FIG. 2 A channel schematic diagram showing a relationship betweenE-RACH, AICH/E-AICH, and E-DCH.

FIG. 3 A sequence chart of channel settings for E-RACH and others.

FIG. 4 A block diagram showing an example of a configuration of a basestation in a wireless communications system according to the presentinvention.

FIG. 5 A block diagram showing an example of a configuration of a mobilestation in the wireless communications system according to the presentinvention.

FIG. 6 A sequence chart showing a procedure of data transmission infirst and second embodiments of the present invention.

FIG. 7 A first schematic diagram of allocation of a default E-DCHresource configuration in the first embodiment of the present invention.

FIG. 8 A second schematic diagram of allocation of a default E-DCHresource configuration in the first embodiment of the present invention.

FIG. 9 A flow chart showing an operation of the base station in thefirst and second embodiments of the present invention.

FIG. 10 A flow chart showing an operation of the mobile station in thefirst and second embodiments of the present invention.

FIG. 11 A first schematic diagram of allocation of a default E-DCHresource configuration in the second embodiment of the presentinvention.

FIG. 12 A second schematic diagram of allocation of a default E-DCHresource configuration in the second embodiment of the presentinvention.

FIG. 13 A flow chart showing an operation of modifying broadcastinformation in the base station in the second embodiment of the presentinvention.

FIG. 14 A sequence chart showing a procedure of data transmission in athird embodiment of the present invention.

FIG. 15 A flow chart showing an operation of the base station in thethird embodiment of the present invention.

FIG. 16 A flow chart showing an example in which an E-DCH resourceconfiguration is available in the E-DCH resource configuration list.

FIG. 17 A flow chart showing an example in which no E-DCH resourceconfiguration is available in the E-DCH resource configuration list.

EXPLANATION OF SYMBOLS

-   -   10 Base station    -   20 Mobile station    -   101 Wireless communication section    -   102 Uplink signal reception processing section    -   103 Uplink signal transmission processing section    -   104 Communication section    -   105 Downlink signal reception processing section    -   106 Downlink signal transmission processing section    -   107 Resource configuration generating section    -   108 Preamble identifying section    -   109 Resource configuration control section    -   201 Wireless communication section    -   202 Reception processing section    -   203 Responsive notification processing section    -   204 Transmission data control section    -   205 Resource configuration keeping section    -   206 Transmission processing section    -   207 Buffer

BEST MODES FOR CARRYING OUT THE INVENTION

The present invention is characterized in determining a default resourceconfiguration using at least the total number of resource configurationsor a value obtained from the total number.

Now configurations of a base station and a mobile station will bedescribed below with reference to FIGS. 4 and 5, assuming that theresource configuration is an E-DCH resource configuration.

FIG. 4 is a block diagram showing an example of a configuration of abase station in first through third embodiments. A base station 10 isprovided with a wireless communication section 101 for wirelesscommunication with mobile stations 20, an uplink signal receptionprocessing section 102 for processing uplink signals received from themobile stations, an uplink signal transmission processing section 103for performing processing for transmitting data within the uplinksignals to be transferred to an upper network apparatus, such as, forexample, a base station control apparatus, and a communication section104 for transmitting the data to the upper network apparatus. Data fromthe upper network apparatus is received at the communication section104, and then, a downlink signal reception processing section 105applies processing. The processing for transmitting downlink signals tothe mobile stations is performed at a downlink signal transmissionprocessing section 106, and the signals are transmitted to a destinationmobile station from the wireless communication section 101.

The base station 10 is also provided with a preamble identifying section108 connected to the uplink signal reception processing section 102, aresource configuration generating section 107, and a resourceconfiguration control section 109. In a case that a preamble is receivedfrom a mobile station, the uplink signal reception processing section102 transfers it to the preamble identifying section 108; otherwise, tothe uplink signal transmission processing section 103. The preambleidentifying section 108 identifies a preamble signature from thepreamble transferred from the uplink signal reception processing section102, and sends its content to the resource configuration control section109.

The resource configuration generating section 107 generates an E-DCHresource configuration list in which an E-DCH resource configuration iscorrelated with an E-DCH resource configuration index for use in E-RACHfor each predetermined period of time, and outputs the list to theresource configuration control section 109. While the E-DCH resourceconfiguration list is described as being generated and output for eachpredetermined period of time, a mode in which the information ispredetermined may be contemplated.

The resource configuration control section 109 keeps the E-DCH resourceconfiguration list transferred from the resource configurationgenerating section 107, and a preamble signature list containingprespecified information about preamble signatures available for E-RACH.The resource configuration control section 109 outputs the E-DCHresource configuration list and preamble signature list to the downlinksignal transmission processing section 106, which in turn broadcasts theE-DCH resource configuration list received from the transmissionprocessing section 106 to the mobile stations within the cell via thewireless communication section 101.

Moreover, when a result of identification of a preamble is transferredfrom the preamble identifying section 108, and in a case that a defaultE-DCH resource configuration corresponding to the preamble signatureidentified at the preamble identifying section 108 is available in thekept E-DCH resource configuration list, the resource configurationcontrol section 109 transmits a responsive notification ACK to thetransmission processing section 106 using AICH. In a case that thedefault E-DCH resource configuration is not available, and a non-defaultE-DCH resource configuration is available in the E-DCH resourceconfiguration list, an available E-DCH resource configuration isselected from the E-DCH resource configuration list. Furthermore, aresponsive notification NACK using AICH, and an E-AICH signature that isdetermined from an offset value between the default E-DCH resourceconfiguration and the selected E-DCH resource configuration, and anE-AICH signature state using E-AICH are transmitted to the transmissionprocessing section 106.

In a case that the default E-DCH resource configuration is notavailable, and no E-DCH resource configuration is available in the E-DCHresource configuration list, NACK using AICH and NACK using E-AICH aretransmitted to the transmission processing section 106. The transmissionprocessing section 106 uses AICH to transmit a responsive notificationin response to the preamble transferred from the resource configurationcontrol section 109, and incorporates the E-AICH signature state intoE-AICH and uses an E-AICH signature pattern corresponding to the E-AICHsignature to transmit information about the E-DCH resource configurationto the mobile station via the wireless communication section 101.

While the E-DCH resource configuration list is described here as beingkept in the resource configuration control section 109, a mode in whichthe list is kept in the resource configuration generating section 107may be contemplated, or another storage may be provided for keeping it.This requires an operation of sending the E-DCH resource configurationlist from the E-DCH resource configuration generating section 107 to theresource configuration control section 109, or an operation of loadingit from the resource configuration generating section 107 or storage bythe resource configuration control section 109.

It should be noted that functions equivalent to those of the preambleidentifying section 108, resource configuration generating section 107and resource configuration control section 109 may be implemented byrunning programs of respective corresponding functions on aprogram-controlled processor such as a CPU. Moreover, the drawings hereshow portions relating to the channel allocation method according to thepresent invention, and other portions in the configuration are omitted.

FIG. 5 is a block diagram showing an example of a configuration of amobile station in the first through third embodiments. A mobile station20 comprises a wireless communication section 201 for wirelesscommunication with a base station, a reception processing section 202, aresponsive notification processing section 203, a transmission datacontrol section 204, a resource configuration keeping section 205, atransmission processing section 206, and a buffer 207. Again, thedrawing shows portions relating to the channel allocation methodaccording to the present invention, and other portions in theconfiguration are omitted.

The reception processing section 202 receives data from a base stationvia the wireless communication section 201, and in a case that the datais a responsive notification in response to a preamble, it transfers thedata to the responsive notification processing section 203; or in a casethat the data is an E-DCH resource configuration list, it transfers thelist to the resource configuration keeping section 205. The resourceconfiguration keeping section 205 keeps the transferred E-DCH resourceconfiguration list. The responsive notification processing section 203extracts the responsive notification for AICH in response to thepreamble supplied via the reception processing section 202, and in acase that the responsive notification using AICH is NACK, an offsetvalue obtained from the E-AICH signature decoded using the E-AICHsignature pattern and the E-AICH signature state contained in E-AICH.The responsive notifications for AICH and E-AICH are transferred to thetransmission data control section 204. While the E-DCH resourceconfiguration list is described as being received, a mode in which theinformation is kept in mobile stations beforehand may be contemplated.

The transmission data control section 204 invokes the E-DCH resourceconfiguration list kept in the resource configuration keeping section205, determines an E-DCH resource configuration for use in E-RACH fromthe responsive notifications for AICH and E-AICH supplied via theresponsive notification processing section 203 and the invoked E-DCHresource configuration list, and outputs it to the transmissionprocessing section 206. The transmission processing section 206configures an E-DCH transmission profile based on the E-DCH resourceconfiguration supplied as input from the transmission data controlsection 204, and transmits the data to the base station via the wirelesscommunication section 201.

While the kept E-DCH resource configuration list is described here asbeing kept in the resource configuration keeping section 205, a mode inwhich the list is transmitted directly from the reception processingsection 202 or via the resource configuration keeping section 205 to thetransmission data control section 204 for keeping the list therein maybe contemplated. This eliminates the need for processing of loading theE-DCH resource configuration list from the resource configurationkeeping section 205 via the transmission data control section 204.

The buffer 207 keeps data to be transmitted when it appears. It alsopasses the kept data to the transmission data control section whentransmission processing is performed.

It should be noted that functions equivalent to those of the responsivenotification processing section 203 and transmission data controlsection 204 may be implemented by running programs of respectivecorresponding functions on a program-controlled processor such as a CPU.

First Embodiment

This embodiment is characterized in determining a default resourceconfiguration from the preamble signature number, and the total numberof resource configurations or a value obtained from that total number.

Now an exemplary wireless communications system for datatransmission/reception will be described with reference to FIGS. 6-10,in which the resource configuration is an E-DCH resource configuration,and the total number of E-DCH resource configurations is directly usedto calculate an E-DCH resource configuration index to be allocated bydefault from the broadcast preamble signature list, E-DCH resourceconfiguration list, and the remainder of the preamble signature numberdivided by the total number of E-DCH resource configurations.

FIG. 6 is a sequence chart showing a procedure of data transmission inthis embodiment. A base station broadcasts an E-DCH resourceconfiguration list and a preamble signature list using BCH to mobilestations within a cell for each predetermined period of time (StepS101). The resource configuration keeping section 205 in a mobilestation keeps the received broadcast information, and when it hasreceived new broadcast information, it updates the information. At thattime, the mobile station and base station individually calculate anE-DCH resource configuration index to be allocated by default from theremainder of the preamble signature number divided by the total numberof E-DCH resource configurations from the broadcast information based onEQ. (4) below (Step S102):

[Equation 4]

Dind=Preind mod Y  (4)

where Dind designates an E-DCH resource configuration index to beallocated by default, Preind designates a preamble signature number, andY designates the total number of E-DCH resource configurations.

Once transmission data has appeared in the buffer 207 in the mobilestation (Step S103), the mobile station, particularly, the transmissiondata control section 204, transmits a preamble to the base station asdescribed above (Step S104). Upon receipt of the preamble, the basestation performs processing of an AICH/E-AICH response conditiondecision step for deciding whether the default E-DCH resourceconfiguration corresponding to a received preamble signature isavailable (Step S105). The AICH/E-AICH response condition decision stepcalculates a default E-DCH resource configuration corresponding to thereceived preamble signature using EQ. (4) given above.

Once the base station has received a preamble, processing according toone of Alt 2-1, 2-2, 2-3 is performed depending upon the decision at theAICH/E-AICH response condition decision step. In a case that the basestation cannot recognize a preamble because, for example, the preamblecannot be received at the base station although it was transmitted bythe mobile station, the base station makes no special notification tothe mobile station, and waits for any action from the mobile station inAlt 1. In Alt 1, the mobile station retransmits the preamble after apredetermined period of time from the transmission of the preamble atStep S104 (Step S106), and the base station performs processing at theAICH/E-AICH response condition decision step again.

In a case that the calculated E-DCH resource configuration is availableat the AICH/E-AICH response condition decision step, processing in Alt2-1 is performed. In Alt 2-1, a responsive notification ACK istransmitted to the mobile station using AICH (Step S107), and the mobilestation determines an E-DCH transmission profile from the default E-DCHresource configuration calculated using EQ. (4) given earlier (StepS108), and transmits uplink data (Step S109).

In a case that in the AICH/E-AICH response condition decision step, thedefault E-DCH resource configuration is not available, and a non-defaultE-DCH configuration is available in the E-DCH resource configurationlist, processing in Alt 2-2 is performed. In Alt 2-2, a responsivenotification NACK using AICH and a state including an E-AICH signaturestate using E-AICH are transmitted to the mobile station. Intransmitting the information, an E-AICH signature pattern correspondingto an E-AICH signature obtained from an offset value between the defaultE-DCH resource configuration and the selected E-DCH resourceconfiguration is used (Step S110).

The mobile station uses the E-AICH signature pattern to decode E-AICH.The resulting E-AICH signature and E-AICH signature state from decodingare used in combination to extract an offset value. Moreover, an E-DCHresource configuration for use in transmission is determined from theextracted offset value and the default E-DCH resource configuration. AnE-DCH transmission profile is determined from the determined E-DCHresource configuration (Step S111), and uplink data is transmitted (StepS112).

In a case that in the AICH/E-AICH response condition decision step, noE-DCH resource configuration is available or the default E-DCH resourceconfiguration cannot be used in a base station that does not supportE-AICH, processing in Alt 2-3 is performed. In Alt 2-3, a responsivenotification NACK is transmitted to the mobile station using AICH for abase station that does not support E-AICH, and a responsive notificationNACK is transmitted there using AICH and

E-AICH for a base station that supports E-AICH (Step S113). Thereafter,the mobile station checks a retransmission counter (Step S114). In acase that the remaining count in the retransmission counter is non-zero,the processing in Alt 2-3-1 of retransmitting the preamble after apredetermined wait time is performed (Step S115); or in a case that theremaining count in the retransmission counter is zero, the processing atAlt 2-3-2 of aborting data transmission is performed (Step S116).

Now Step 102 of calculating a default E-DCH resource configuration indexwill be described with reference to FIGS. 7 and 8.

FIG. 7 shows an example of correspondence between a preamble signaturenumber and an E-DCH resource configuration index in a case that thenumber of E-DCH resource configurations is greater than the number ofpreamble signatures. In this case, the E-DCH resource configurationindex allocated by default matches the preamble signature number. Itshould be noted that in a case that the number of preamble signatures isequal to the number of E-DCH resource configurations, the E-DCH resourceconfiguration index matches the preamble signature number as with FIG.7.

FIG. 8 shows an example of correspondence between a preamble signaturenumber and an E-DCH resource configuration index in a case that thenumber of E-DCH resource configurations is smaller than the number ofpreamble signatures. In this case, for preamble signatures #0-#5, whichare equal to or smaller than the number of E-DCH resourceconfigurations, the E-DCH resource configuration index allocated bydefault matches the preamble signature number, as in the case shown inFIG. 7. However, for the preamble signature #6 and subsequent ones, thenumber of E-DCH resource configurations to be allocated is not enough.Thus, according to EQ. (4), the preamble signature number is divided bythe total number of E-DCH resource configurations, and an E-DCH resourceconfiguration index corresponding to the remainder thereof is allocatedby default.

By the processing, a default E-DCH resource configuration can beallocated regardless of the number of E-DCH resource configurations.

FIG. 9 is a flow chart showing an operation of the base station,particularly, the E-DCH resource configuration control section 109 inthe AICH/E-AICH response condition decision step for deciding a responsefor AICH/E-AICH.

The base station checks whether a preamble transmitted by a mobilestation is received (Step S201), and in a case that no preamble isreceived, it returns to a preamble reception wait state. In a case thata preamble is received at Step S201, a decision is made as to whether adefault E-DCH resource configuration corresponding to the receivedpreamble signature is available (Step S202). In a case that the defaultE-DCH resource configuration is available, the base station uses AICH tosend a responsive notification ACK (Step S203), receives uplink datatransmitted by the mobile station (Step S204), and returns to thepreamble reception wait state at Step S201.

At Step S202, in a case that the default E-DCH resource configuration isnot available, the base station decides whether E-AICH is supported(Step S205). In a case that E-AICH is not supported, AICH is used tosend a responsive notification NACK (Step S206), and the base stationreturns to the preamble reception wait state at Step S201.

At Step S205, in a case that E-AICH is supported, a decision is made asto whether a different E-DCH resource configuration is available (StepS207). In a case that a non-default E-DCH configuration is available inthe E-DCH resource configuration list at Step S207, one of them isselected. Moreover, from the responsive notification NACK using AICH andan offset value between the default E-DCH resource configuration and theselected E-DCH resource configuration, an E-AICH signature and an E-AICHsignature state are obtained, and transmitted using E-AICH (Step S208).The base station receives uplink data transmitted by the mobile station(Step S209), and returns to the preamble reception wait state at StepS201.

In a case that none of E-DCH resource configurations is available atStep S207, a responsive notification NACK using AICH and a responsivenotification NACK using E-AICH are sent (Step S210), and the basestation returns to the preamble reception wait state at Step S201.

Now the operation at Step S207 will be concretely illustrated withreference to FIGS. 16 and 17. The E-DCH resource configuration controlsection 109 keeps information representing whether an E-DCH resourceconfiguration is available. In FIGS. 16 and 17, ‘Busy’ represents theresource configuration is busy and ‘Available’ represents the resourceconfiguration is available. While the binary value is taken in thedescription here, information representing the status of an E-DCHresource configuration is not limited to such a binary value. Moreover,in the examples shown in FIGS. 16 and 17, a default E-DCH resourceconfiguration is assumed to be that with an E-DCH resource configurationindex #0.

FIG. 16 shows an example in which an E-DCH resource configuration isavailable in the E-DCH resource configuration list. Since the defaultE-DCH resource configuration is busy, the base station selects an E-DCHresource configuration index #4, which is available. Since an offsetbetween the default E-DCH resource configuration and the selected E-DCHresource configuration is four, the base station obtains an E-AICHsignature of #2 and an E-AICH state of +1 based on Table 3. Moreover,information including the E-AICH state of +1 is sent to the mobilestation using E-AICH, along with an E-AICH signature patterncorresponding to the E-AICH signature #2.

FIG. 17 shows an example in which no E-DCH resource configuration isavailable in the E-DCH resource configuration list. This example shows acase in which no E-DCH resource configuration is available, so that thebase station transmits NACK. Based on Table 3, NACK corresponds to anE-AICH signature #0 and an E-AICH state of +1. Hence, informationcontaining an E-AICH state of +1 is sent to the mobile station usingE-AICH along with an E-AICH signature pattern corresponding to theE-AICH signature #0.

FIG. 10 is a flow chart showing an operation of the mobile station,particularly, the transmission data control section 204, in thisembodiment. In response to the event of transmission data appearing inthe buffer 207, the mobile station starts a control operation in FIG.10. The mobile station decides whether broadcast information is receivedfrom a base station (Step S301). In a case that broadcast information isreceived, a default E-DCH resource configuration to be allocated foreach preamble signature number is calculated from the broadcastinformation according to the aforementioned method (Step S302), and aretransmission counter M is initialized to an initial value Minit (StepS303). In a case that no broadcast information is received, the mobilestation waits for reception of broadcast information, and the flow goesback to Step S301. After Step S303, processing at the preambletransmitting step for transmitting a preamble to the base station isperformed (Step S304). Thereafter, the mobile station turns to anAICH/E-AICH responsive notification reception wait state in which aresponsive notification from the base station is waited for, and aresponsive notification for AICH is checked (Step S305).

At Step S305, in a case that a responsive notification from the basestation using AICH is ACK, the mobile station uses the default E-DCHresource configuration calculated at Step S302 to determine an E-DCHtransmission profile, transmits uplink data to the base station (StepS306), and the process is terminated.

In a case that a responsive notification from the base station usingAICH is NACK at Step S305, an E-AICH signature pattern is used to decodean E-AICH signature. The resulting E-AICH signature from decoding andthe E-AICH signature state are used in combination to check a responsivenotification for E-AICH (Step S307). In a case that the responsivenotification using E-AICH contains an offset value indicating an E-DCHresource configuration at Step S307, an offset E-DCH resourceconfiguration is used to determine an E-DCH transmission profile, uplinkdata is transmitted to the base station (Step S308), and the process isterminated. In a case that the responsive notification for E-AICH isNACK, or the base station notifies the mobile station that E-AICH is notsupported at Step S307, a retransmission counter M is checked whether itis zero (Step S309). In a case that the retransmission counter M iszero, data transmission is aborted and the process is terminated. In acase that the result at Step S309 is non-zero, the retransmissioncounter M is decremented by one (Step S310), a predetermined period oftime is waited (Step S311), and the flow goes back to the preambletransmitting step (Step S304).

At Step S305, in a case that no responsive notification for AICH isreceived from the base station for a predetermined period of time, theremaining count of the retransmission counter M is checked (Step S312).In a case that the remaining count of the retransmission counter iszero, data transmission is aborted and the process is terminated. In acase that the result at Step S309 is non-zero, the retransmissioncounter M is decremented by one (Step S313), a predetermined period oftime is waited (Step S314), and the flow goes back to the preambletransmitting step (Step S304).

In this embodiment, since a default E-DCH resource configuration to beallocated for each preamble signature is calculated from existingbroadcast information, the need for adding the amount of broadcastinformation is eliminated and a decrease of downlink wireless capacitycan be prevented.

While the description in this embodiment has addressed a case in whichthe preamble signature number is used in determining a default E-DCHresource configuration, a value calculated from the preamble signaturenumber, such as, for example, A×(preamble signature number)+B (where Aand B are zero, or positive or negative integers), may be employed inplace of the preamble signature number itself. Moreover, the value foruse in calculation of the remainder is not limited to the preamblesignature number, and it may be a value for identifying the time such asa slot number with which the mobile station has transmitted RACH, or anumber for identifying each mobile station.

Moreover, while in this embodiment, the description has addressed a casein which the total number of E-DCH resource configurations is used indetermining a default E-DCH resource configuration, it is not necessaryto use the total number, and a mode in which a number less than thetotal number of E-DCH resource configurations is used may becontemplated. By taking such a mode, an E-DCH resource configurationthat is not set by default can be specified for any mobile station toprovide an effect that an E-DCH resource configuration to be used can beflexibly selected.

It should be noted that in obtaining correspondence between the preamblesignature number and default E-DCH resource configuration, theobtainment is not limited to the mode in which a remainder is taken asin this embodiment, and any mode that can support a range of the totalnumber of E-DCH resource configurations, such as one employing a hashfunction, may be contemplated.

While the description in this embodiment has addressed a case in whichthe resource configuration is an E-DCH resource configuration, it isobvious that any system that transmits data using a resourceconfiguration corresponding to a default resource configuration when amobile station has received the aforementioned first response may beemployed and the resource configuration is not limited to the E-DCHresource configuration.

Second Embodiment

In this embodiment, a base station is characterized in preparing aplurality of default resource configurations for each preamblesignature, preparing a plurality of values of a parameter forcalculating a default resource configuration, selecting a value of theparameter, and broadcasting it.

Now an exemplary wireless communications system will be described withreference to FIGS. 9 through 13, in which a resource configuration is anE-DCH resource configuration, a plurality of offsets are providedbeforehand to calculate an E-DCH resource configuration index to beallocated by default, and the base station changes a group of defaultuplink channel resource configurations for use depending upon autilization state of the group.

In the first embodiment, only one default E-DCH resource configurationis allocated for each preamble signature. This results in a higherprobability that a default E-DCH resource configuration is busy when amobile station transmits a preamble, and an E-DCH resource configurationdifferent from the default one is allocated using E-AICH. Thus, themobile station cannot know an allocated E-DCH resource configurationuntil E-AICH is decoded, and the amount of decoding processing at themobile station is increased.

Moreover, for a base station that does not support an E-AICH, an E-DCHresource configuration other than a default one cannot be allocatedusing E-AICH, so that the probability of collision of E-DCH resourceconfigurations may be higher. Thus, this embodiment is characterized inthat a plurality of default E-DCH resource configuration groups aredefined for a preamble signature, and the base station changes a groupof default E-DCH resource configurations for use depending upon autilization state of the group.

FIG. 6 is a data transmission sequence chart in this embodiment. This issimilar to that in the first embodiment except for an operation ofbroadcasting an E-DCH resource configuration list (Step S101) and anoperation of calculating an E-DCH resource configuration index to beallocated by default from the broadcast information (Step S102), andexplanations for others will be omitted.

At Step S101, the base station broadcasts an E-DCH resourceconfiguration list, a preamble signature list available in E-RACH, apositional offset B, and a spacing offset C, which will be describedlater, to mobile stations within a cell using BCH for each predeterminedperiod of time. The base station manages utilization states of aplurality of default E-DCH resource configuration groups, which will bedescribed later, at the resource configuration control section 109, andmodifies the broadcast information depending upon the utilization ratesof the default E-DCH resource configuration groups. At Step 102, themobile station and base station calculate a default E-DCH resourceconfiguration index from the E-DCH resource configuration list,according to the broadcast information based on EQ. (5) below:

[Equation 5]

Dind=(C×Preind+B)mod Y  (5)

where, as in the first embodiment, Dind designates an E-DCH resourceconfiguration index to be allocated by default, Preind designates apreamble signature number, and Y designates the total number of E-DCHresource configurations. In the E-DCH resource configuration list, Bdesignates a parameter offsetting the default position (which parameterwill be referred to as positional offset hereinbelow), and C designatesa parameter representing spacing between default E-DCH resourceconfiguration indices corresponding to preamble signatures havingconsecutive numbers (which parameter will be referred to as spacingoffset). The values of the positional offset B and spacing offset C areperiodically broadcast by the base station. FIG. 11 is an exampleshowing allocation of default E-DCH resource configurations based on EQ.(5). In this example, positional offset B=2, and spacing offset C=2.

Now a specific example of the method of modifying broadcast informationdepending upon utilization rates of default E-DCH resource configurationgroups will be described with reference to FIGS. 12 and 13.

FIG. 12 is an example showing allocation of default E-DCH resourceconfigurations in this example. FIG. 13 is a flow chart showing anoperation of modifying broadcast information at a base station.

In the example of FIG. 12, the base station specifies two default E-DCHresource configurations for each of all signature preambles that arevalid within a cell based on EQ. (6) below, and manages eachconfiguration as Default Group. It is assumed here that C1=2, B1=2, andB2=3, and Default Group 1 is used for initial setting.

[Equation 6]

Default Group1=(C1×Preind+B1)mod Y

Default Group2=(C1×Preind+B2)mod Y  (6)

where C1>|B2−B1|

In FIG. 13, in response to determination of information to be broadcastfor each predetermined period of time, a control operation is started. Autilization rate R(x) for Default Group is calculated based on EQ. (7)below:

[Equation 7]

R(x)=Rbusy(x)/Rall(x)  (7)

where Rbusy(x) designates the number of busy E-DCH resourceconfigurations in Default Group #x, and Rall(x) designates the totalnumber of E-DCH resource configurations in Default Group #x.

Then, the calculated utilization rate R(x) is compared with apredetermined threshold Rth (Step S701), where x corresponds to theDefault Group number. Since Default Group 1 is initially set in thisexample, R(1) is calculated and compared with the threshold Rth.

In a case that the threshold Rth is not exceeded at Step S701, nomodification is applied to the positional offset B, and the flow goesback to Step S701. In a case that the utilization rate R(x) is greaterthan the threshold Rth, the base station calculates a utilization ratefor a Default Group different from the currently used Default Group, andcompares it with the utilization rate R(x) (Step S702). In this example,R(2) is calculated for a Default Group 2 different from the currentlyused Default Group 1 and compared with R(1). In a case that theutilization rate R(x) for the currently used Default Group is lower thanthat for the Default Group different from the currently used DefaultGroup at Step S702, no modification is applied to the positional offsetB and the flow goes back to Step S701.

In a case that the utilization rate R(x) for the currently used DefaultGroup is higher than that for the Default Group different from thecurrently used Default Group at Step S702, the base station selects aDefault Group having a lower utilization rate, and broadcasts apositional offset B corresponding to the Default Group to mobilestations within the cell (Step S703). In this example, in a case thatR(1) is higher than R(2), the base station selects a positional offsetB2 corresponding to the Default Group having a lower utilization rate,and broadcasts it to mobile stations within the cell.

FIG. 9 is a flow chart showing an operation of a base station in thisembodiment, which is similar to that in the first embodiment anddescription thereof will be omitted.

FIG. 10 is a flow chart showing an operation of a mobile station in thisembodiment, which is similar to that in the first embodiment anddescription thereof will be omitted.

While in this embodiment, two groups of default E-DCH resourceconfigurations are specified and decision is made according to a high orlow utilization rate R(x), the number of groups is not limited to two. Asimilar effect can be provided when three or more groups are specified,and a positional offset value corresponding to a group having the lowestutilization rate R(x) is selected at Step S702.

While in this embodiment, the description has addressed a case in whichthe base station changes a default E-DCH resource configuration group tobe used depending upon a utilization state of the group, a mode in whichthe group is periodically modified in a cycle of a specified period oftime.

According to this embodiment, a plurality of groups of default E-DCHresource configurations are specified for a preamble signature, and abase station changes a default E-DCH resource configuration group to beused depending upon the utilization state of the group, so that theprobability that a default E-DCH resource configuration can be used isimproved to reduce a frequency at which an E-DCH resource configurationis allocated using E-AICH, thus reducing the processing load on mobilestations.

Moreover, according to this embodiment, a plurality of default E-DCHresource configuration groups are defined for a preamble signature, anda base station changes a default E-DCH resource configuration group tobe used depending upon the utilization state of the group, theprobability that a default E-DCH resource configuration can be used isimproved, thus reducing the probability of collision of E-DCH resourceconfigurations in a base station in which E-AICH cannot be used.

Third Embodiment

In this embodiment, a base station is characterized in preparing aplurality of the aforementioned default resource configurations for eachpreamble signature, preparing a plurality of values of a parameter forcalculating a default resource configuration, and broadcasting them.

Now an exemplary wireless communications system will be described withreference to FIGS. 10, 12, 14, and 15, in which a resource configurationis an E-DCH resource configuration, a plurality of offsets are providedbeforehand to calculate an E-DCH resource configuration index to beallocated by default, and a base station uses an appropriate defaultE-DCH resource configuration group depending upon the time at which amobile station transmits a preamble.

In the first embodiment, only one default E-DCH resource configurationis allocated for each preamble signature. This results in a higherprobability that a default E-DCH resource configuration is busy when amobile station transmits a preamble, and an E-DCH resource configurationdifferent from the default one is allocated using E-AICH. Thus, themobile station cannot know an allocated E-DCH resource configurationuntil E-AICH is decoded, and the amount of decoding processing at themobile station is increased.

Moreover, for a base station that does not support E-AICH, an E-DCHresource configuration other than a default one cannot be allocatedusing E-AICH, so that the probability of collision of E-DCH resourceconfigurations may be higher. Thus, this embodiment is characterized inthat a plurality of default E-DCH resource configuration groups aredefined for each preamble signature, and the base station uses anappropriate default E-DCH resource configuration group depending uponthe time at which the mobile station transmits a preamble.

FIG. 14 is a data transmission sequence chart in this embodiment. Thisis similar to that in the first embodiment except for an operationrelating to decision of an E-DCH resource configuration group (StepsS801-S807) and an operation of determining an E-DCH resourceconfiguration for use in transmitting uplink data by the mobile station(Step S808 or Step S811), and explanations for others will be omitted.

At Step S801, the base station broadcasts an E-DCH resourceconfiguration list, a preamble signature list available in E-RACH, andtwo setting values using a positional offset B and an a spacing offset Cas defined in the second embodiment, to mobile stations within a cellusing BCH for each predetermined period of time. At Step S802, themobile station and base station calculate a default E-DCH resourceconfiguration index from broadcast information based on EQS. (5) and (6)as in the second embodiment to determine two Default Groups.

Once transmission data has appeared in the buffer 207 in the mobilestation (Step S803), the transmission data control section 204 transmitsa preamble to the base station (Step S804). Upon receipt of thepreamble, the base station decides whether a default E-DCH resourceconfiguration is available (Step S805).

In a case that a default E-DCH resource configuration corresponding tothe received preamble signature is not available, and the preambleretransmission counter C does not exceed a threshold Cth at Step S805,the base station increments the retransmission counter by one. The basestation makes no special notification to the mobile station, and waitsfor any action from the mobile station in the processing in Alt 1. InAlt 1, the mobile station retransmits the preamble after a predeterminedperiod of time from the transmission of the preamble at Step S804according to the method described above (Step S806), and the basestation performs processing at Step S805 again. The processing in Alt 1is also performed in a case that the base station cannot recognize apreamble because, for example, the preamble cannot be received at thebase station although it was transmitted by the mobile station. Whilethe description here has addressed a case in which retransmission of apreamble at Step S306 is performed after a predetermined period of time,a mode in which it is performed after a certain access slot has passedmay be contemplated.

In a case that a default E-DCH resource configuration corresponding tothe received preamble signature is available, or the preambleretransmission counter C is greater than the threshold Cth at Step S805,processing in one of Alt 2-1-Alt 2-3 is performed. In a case that adefault E-DCH resource configuration corresponding to the receivedpreamble signature is available, the flow goes to processing in Alt 2-1.In a case that a default E-DCH resource configuration corresponding tothe received preamble signature is not available, and the preambleretransmission counter C exceeds the threshold Cth, the flow goes toprocessing in Alt 2-2. A detailed description of the operation of thebase station will be made with reference to FIG. 15. In determining anE-DCH resource configuration for use in transmitting uplink data, suchas in Step S808 in Alt 2-1 or Step S811 in Alt 2-2, the mobile stationdetermines a default E-DCH resource configuration from the Default Group1 in a case that the access slot number with which the preamble istransmitted is even, or determines it from the Default Group 2 in a casethat the access slot number with which the preamble is transmitted isodd.

While the description here has addressed a case in which the basestation makes no special notification to the mobile station in a casethat a default E-DCH resource configuration corresponding to thereceived preamble signature is not available and the preambleretransmission counter C does not exceed the threshold Cth at Step S805,a mode in which a base station that does not support E-AICH transmits aresponsive notification NACK using AICH as in Alt 2-3, and a basestation that supports E-AICH transmits a responsive notification NACKusing AICH and E-AICH may be contemplated.

FIG. 15 is a flow chart showing an operation of the base station,particularly, the resource configuration control section 109, at StepS805 for deciding a response for AICH/E-AICH in this embodiment. Thebase station checks whether a preamble transmitted by the mobile stationis received (Step S901), and in a case that no preamble is received, itreturns to a preamble reception wait state. In a case that a preamble isreceived at Step S901, a decision is made as to whether a default E-DCHresource configuration allocated to the received preamble is availabletaking account of the access slot number with which the mobile stationhas transmitted the preamble (Step S902). In a case that the defaultE-DCH resource configuration allocated for the received time isavailable, the base station uses AICH to send a responsive notificationACK (Step S903), receives uplink data transmitted by the mobile station(Step S904), and returns to the preamble reception wait state at StepS901.

At Step S902, in a case that a default E-DCH resource configurationallocated to the received preamble is not available, the base stationdecides whether the preamble wait counter C exceeds the threshold Cth(Step S905). In a case that the preamble wait counter C exceeds thethreshold Cth at Step S905, the base station decides whether anon-default E-DCH configuration is available in the E-DCH resourceconfiguration list (Step S906).

In a case that a non-default E-DCH resource configuration is availablein the E-DCH resource configuration list at Step S906, one of those inthe list is selected, a responsive notification NACK using AICH istransmitted and along therewith, an E-AICH signature and an E-AICHsignature state are obtained from an offset value between the defaultE-DCH resource configuration and the selected E-DCH resourceconfiguration, and an E-AICH signature pattern corresponding to theE-AICH signature is used to transmit E-AICH including the E-AICHsignature state (Step S907). The base station receives uplink datatransmitted by the mobile station (Step S908), and returns to thepreamble reception wait state at Step S901.

In a case that no non-default E-DCH resource configuration is availablein the E-DCH resource configuration list at Step S906, the base stationsends a responsive notification NACK using AICH and a responsivenotification NACK using E-AICH (Step S909), and returns to the preamblereception wait state at Step S901.

In a case that the timing wait counter C does not exceed the thresholdCth at Step 905, the base station adds one to the timing wait counter C(Step S910), and returns to the preamble reception wait state at StepS901.

FIG. 8 is a flow chart showing an operation of the mobile station inthis embodiment, which is similar to that in the first embodiment anddescription thereof will be omitted.

While in this embodiment, two default E-DCH resource configurationgroups are set, and a group to be used is decided according to evennessor oddness of the access slot with which a preamble is transmitted, asimilar effect can be obtained by setting three or more groups anddividing access slots in the same number to decide a group to be used.

For example, when the retransmission interval for a preamble is an oddnumber of access slots, in a case that two default E-DCH resourceconfiguration groups are set, an even-numbered access slot and anodd-numbered access slot are cycled to transmit a preamble, andtherefore, the base station can alternately use an appropriate defaultE-DCH resource configuration group.

Moreover, when the transmission interval for a preamble is an evennumber of access slots, a default E-DCH resource configuration group maybe appropriately used by setting three or more such groups.

While the description of this embodiment has addressed a case in which agroup to be used is changed depending upon the time at which the mobilestation transmits a preamble, a mode in which a group to be used ischanged periodically depending upon a specified time may becontemplated.

This embodiment is characterized in that at least a value obtained fromthe total number of resource configurations is used to define aplurality of default E-DCH resource configuration groups for onepreamble signature, and the base station uses an appropriate defaultE-DCH resource configuration group depending upon the time at which amobile station transmits a preamble.

According to this embodiment, a plurality of default E-DCH resourceconfiguration groups are defined for a preamble signature, and dependingupon the time at which a mobile station transmits a preamble, a basestation uses an appropriate default E-DCH resource configuration group,whereby reduction of the processing load on the mobile station can beexpected. This is because the frequency at which a non-default E-DCHresource configuration is allocated using E-AICH can be reduced by usingan appropriate default E-DCH resource configuration group to improve theprobability that a default E-DCH resource configuration can be used.

Moreover, a plurality of default E-DCH resource configuration groups aredefined for a preamble signature, and depending upon the time at which amobile station transmits a preamble, a base station uses an appropriatedefault E-DCH resource configuration group to improve the probabilitythat a default E-DCH resource configuration can be used, whereby theprobability of collision of E-DCH resource configurations is reduced.

The present invention is applicable to a wireless communications systemin which a plurality of wireless communication apparatuses use an uplinkchannel to access a base station.

The present application claims priority based on Japanese PatentApplication No. 2008-072580 filed on Mar. 19, 2008, disclosure of whichis incorporated herein in its entirety.

1. A method comprising: selecting a signature; transmitting a preambleusing the signature; receiving, on an acquisition indicator channel(AICH), a signal including an acquisition indicator, wherein theacquisition indicator corresponds to the signature; calculating adefault E-DCH resource index X as X=Dind mod Y, wherein the Dind is anindex of the signature and the Y is a total number of E-DCH resourceconfigurations; and controlling an E-DCH transmission based on thedefault E-DCH resource index X, in a case where the acquisitionindicator is positive.
 2. The method according to claim 1 furthercomprising, calculating a resource configuration index based on the X,the Y, EAI_(s′) and signature s′, wherein the EAI_(s′) is included inthe signal; and controlling an E-DCH transmission based on the resourceconfiguration index, in a case where the acquisition indicator isnegative.
 3. A mobile station comprising: a processor configured toselect a signature; a transmitter configured to transmit a preambleusing the signature; and a receiver configured to receive, on anacquisition indicator channel (AICH), a signal including an acquisitionindicator, wherein the acquisition indicator corresponds to thesignature, wherein the processor configured to calculate a default E-DCHresource index X as X=Dind mod Y, wherein the Dind is an index of thesignature and the Y is a total number of E-DCH resource configurations,and wherein the processor is configured to control an E-DCH transmissionbased on the default E-DCH resource index X, in a case where theacquisition indicator is positive.
 4. The mobile station according toclaim 3, wherein the processor is configured to calculate a resourceconfiguration index based on the X, the Y, EAI_(s′) and signature s′,wherein the EAI_(s′) is included in the signal, and wherein theprocessor is configured to control an E-DCH transmission based on theresource configuration index, in a case where the acquisition indicatoris negative.
 5. A method comprising: receiving a preamble from a mobilestation, wherein the preamble includes a signature; transmitting, on anacquisition indicator channel (AICH), a first signal including anacquisition indicator, wherein the acquisition indicator corresponds tothe signature; and receiving a second signal of an E-DCH based on adefault E-DCH resource index X in a case where the acquisition indicatoris positive, wherein the default E-DCH resource index X is calculated asX=Dind mod Y, and wherein the Dind is an index of the signature and theY is a total number of E-DCH resource configurations.
 6. The methodaccording to claim 5 further comprising, receiving a third signal of theE-DCH based on a resource configuration index, wherein the resourceconfiguration index is calculated based on the X, the Y, EAI_(s′) andsignature s′ in a case where the acquisition indicator is negative, andwherein the EAI_(s′) is included in the first signal.
 7. A base stationcomprising: a receiver configured to receive a preamble from a mobilestation, wherein the preamble includes a signature; and a transmitterconfigured to transmit, on an acquisition indicator channel (AICH), afirst signal including an acquisition indicator, wherein the acquisitionindicator corresponds to the signature, wherein the receiver isconfigured to receive a second signal of an E-DCH based on a defaultE-DCH resource index X in a case where the acquisition indicator ispositive, wherein the default E-DCH resource index X is calculated asX=Dind mod Y, and wherein the Dind is an index of the signature and theY is a total number of E-DCH resource configurations.
 8. The basestation according to claim 7, wherein the receiver is configured toreceive a third signal of the E-DCH based on a resource configurationindex, wherein the resource configuration index is calculated based onthe X, the Y, EAI_(s′) and signature s′ in a case where the acquisitionindicator is negative, and wherein the EAI_(s′) is included in the firstsignal.